(2x+y)^ - (x-2y)^
(2x+y)(2x+y) - (x-2y)(x-2y)
4x^ + 2xy + 2xy + y^ - x^ + 2xy + 2xy - 4y^
3x^ - 3y^ + 8xy , I believe ! I'm not 100% on this one though, sorry,!!
(^ is ^2 !!)